Issue 28, 2019

Weakly charged droplets fundamentally change impact dynamics on flat surfaces

Abstract

Electric charges are often found in naturally or artificially formed droplets, such as raindrops and those generated by Kelvin's water dropper. In contrast to the impact of neutral droplets on a flat solid surface upon which a thin convex lens shape layer of the gas film is typically formed, we show that the delicate gas thin film can be fundamentally altered for even weakly charged droplets. As the charge level is raised above a critical level of ∼1% of the Rayleigh limit for representative impact conditions, the Maxwell stress overcomes the gas pressure buildup to deform the droplet bottom surface. A conical liquid tip forms and pierces through the gas film, leading to a circular contact line moving outwards that does not trap any gas. The critical charge level only depends on the capillary number based on the gas viscosity. This finding applies to common liquids and molten alloy droplets, providing new insights into a range of applications such as mitigating pinhole defects in additive manufacturing.

Graphical abstract: Weakly charged droplets fundamentally change impact dynamics on flat surfaces

Supplementary files

Article information

Article type
Paper
Submitted
02 May 2019
Accepted
04 Jun 2019
First published
04 Jun 2019

Soft Matter, 2019,15, 5548-5553

Weakly charged droplets fundamentally change impact dynamics on flat surfaces

F. Gao, H. Yi, L. Qi, R. Qiao and W. Deng, Soft Matter, 2019, 15, 5548 DOI: 10.1039/C9SM00895K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements